Cherry

Fruittree Leafroller

Scientific Name: Archips argyrospila

Description of the Pest

The fruittree leafroller overwinters in the egg stage on twigs. Eggs hatch in early spring; larvae are dark green caterpillars with black heads and are about an inch long when fully grown. They pupate inside a webbed leaf shelter. Adult moths emerge in June or July and deposit overwintering eggs. There is one generation each year.

Damage

Larvae feed on leaves and buds, webbing them together to form a protective case. Fruit damage is usually shallow and superficial, and often occurs when leaves and fruit are webbed together.

Management

Regular monitoring each season is important so that prompt action can be taken if damaging populations develop.

Biological Control

A number of parasites, including species of Macrocentrus, Apanteles, and Exochus, attack leafroller larvae. General predators such as green lacewings, assassin bugs, and minute pirate bugs may feed on eggs and larvae. Preservation of natural-enemy populations is an important part of keeping leafroller numbers low. Use selective materials that are least disruptive of biological control when treating other pests.

Organically Acceptable Methods

Sprays of Bacillus thuringiensis and the Entrust formulation of spinosad are acceptable for use on an organically certified crop.

Monitoring and Treatment Decisions

When monitoring at bloom, look for the presence of larvae and feeding damage. (For more information, see MONITORING PESTS AT BLOOM.) If larval damage is evident in the orchard, apply an insecticide from petal fall to preharvest.

Common name

Amount to use**

R.E.I.‡

P.H.I.‡

(trade name)

(conc.)

(dilute)

(hours)

(days)

The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, the pesticide's properties, and application timing. Not all registered pesticides are listed. Always read the label of the product being listed.

COMMENTS: Apply before blossoms open or injury may result. Do not make more than one application per crop season. Pyrethroids applied at this time can disruptive of beneficials.

. . . or . . .

DIAZINON* 50WP

4 lb

1.25 lb

4 days

21

MODE-OF-ACTION GROUP NUMBER1: 1B

COMMENTS: Organophosphate insecticides used during delayed dormancy are very toxic to honey bees. Remove bees from orchard if cover crops or weeds are in bloom. Oil sprays may injure trees that are water-stressed. It is advisable to postpone an oil application to water-stressed trees until winter rains have replenished soil water and the tree bark is noticeably moist. Avoid drift and runoff into surface water or choose alternative materials. Diazinon has been found in surface waters at levels that violate federal and state water quality standards.

. . . or . . .

ESFENVALERATE *

(Asana XL) 0.66EC

4.8-14.5 oz

2.0-5.8 oz

12

14

MODE-OF-ACTION GROUP NUMBER1: 3

COMMENTS: Provides long-term control. May cause serious outbreaks of spider mites. Do not exceed 0.375 lb a.i./acre/season. At10 oz/acre has a 4-week residual; at 14 oz/acre has a 6-week residual. Pyrethroids applied at this time can disruptive of beneficials.

. . . or . . .

LAMBDA-CYHALOTHRIN*

(Warrior II with Zeon)

1.28-2.56 fl oz

0.32-0.84 fl oz

24

14

MODE-OF-ACTION GROUP NUMBER1: 3

COMMENTS: Pyrethroids applied at this time can disruptive of beneficials.

PETAL FALL TO PREHARVEST

A.

METHOXYFENOZIDE

(Intrepid) 2F

16 fl oz

4 fl oz

4

7

MODE-OF-ACTION GROUP NUMBER1: 18A

COMMENTS: Most effective when applied at petal fall. Do not apply more than 16 fl oz/acre/application or 58 fl oz/acre/season. Coverage is extremely important; sprayer speed should not exceed 2 mph.

B.

BACILLUS THURINGIENSIS ssp. KURSTAKI#

(various products)

Label rates

4

0

MODE-OF-ACTION GROUP NUMBER1: 11.B2

COMMENTS: Least harmful to beneficials. Bt is a stomach poison and must be consumed by the leafroller; therefore it is most effective when applied during warm, dry weather when larvae are actively feeding. Most effective against young larvae. Requires more than 1 treatment; apply second application 7-10 days after first.

C.

SPINOSAD

(Entrust)#

1.71-2.5 oz

0.43-0.6 oz

4

7

MODE-OF-ACTION GROUP NUMBER1: 5

COMMENTS: Most effective when applied at petal fall. This product is toxic to bees for 3 hours following treatment; apply in late evening after bees have stopped foraging. Do not apply more than 9 oz/acre/year.

D.

SPINETORAM

(Delegate) WG

4.5-7 oz

1.125-1.75 oz

4

7

MODE-OF-ACTION GROUP NUMBER1: 5

E.

CHLORANTRANILIPROLE

(Altacor)

3-4.5 oz

0.75-1.125 oz

4

10

MODE-OF-ACTION GROUP NUMBER1: 28

COMMENTS: Do not use with an adjuvant. A newer material; impact on beneficials not yet determined. May cause mite flare-ups.

COMMENTS: May cause increased spider mite problems. Do not apply more than 14 qt XLR PLUS/acre/season. The XLR PLUS formulation is less hazardous to honey bees than other formulations of Sevin if applied from late evening to early morning when bees are not foraging.

**

For concentrate applications, use the amount given in 80-100 gal water/acre, or lower if the label allows; for dilute applications, amount is per 100 gal water to be applied in 300-400 gal water/acre, according to label.

‡

Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.

*

Permit required from county agricultural commissioner for purchase or use.

1

Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode-of-action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

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